Jul 18, 2015
The overall severe weather season has been a quiet one across the state, especially across southern Wisconsin. The heat and humidity made its way further north across the state which helped place Wisconsin in the ring of fire region. An impressive MCS (mesoscale convective complex) rolled across the central and southern sections of the state during the morning hours and produced a decent punch of wind damage and heavy rain. The southern end of the squall line, weakened but left an impressed forward propagating gust front that swept through the remainder of southern Wisconsin.
During the early afternoon, the atmosphere recharged with high instability and an approaching mid-level disturbance at 500mb helped to promote rising air which caused thunderstorms to erupt. The gust front from early morning storms, stalled across northern Illinois and retreated northward during the early afternoon that helped produce more wind shear in the lower levels of the atmosphere. This environment was favorable for possible tornadoes where the Storm Prediction Center issued a tornado watch for the region.
After the storms passed, the National Weather Service in Milwaukee/Sullivan confirmed an EF1 tornado in Walworth County. The remainder of far southern Wisconsin experienced heavy rain, strong gusty winds and vivid cloud to ground lightning. In my opinion, this was not a memorable weather event, but with the absence of severe weather since 2011, this may be the event that people remember for 2015.
Video of Strong Outflow winds